Pelvic inflammatory disease (PID) is caused by both sexually transmitted pathogens, including Neiserria gonorrhoeae and Chlamydia trachomatis, and anaerobic and facultative pathogens.The broad, long term goal of this project is to use both culture-based methods and nucleic acid-based technology to characterize the microorganisms recovered from the endometrial tissues of women with suspected pelvic inflammatory disease (PlD).These data will provide novel data on the etiology of PID and will inform appropriate antimicrobic therapy for PID. Our preliminary data suggests that many of the microorganisms recovered from the endometrial biopsy samples of women with suspected PID using culture methodology in our laboratory do not fit any known taxonomic group based on phenotypic characteristics. Specifically, we propose to: 1) describe the microorganisms in 700 endometrial tissue samples obtained from 250 women enrolled in the acute PID cohort and 200 women enrolled in the cervicitis cohort (Core B), 2) apply genetic sequencing methodology to characterize the novel organisms recovered from the endometrial samples in order to place these organisms into taxonomic groups and to assess whether some organisms are more strongly associated with histologic evidence of endometritis and the signs and symptoms of acute PID, 3) perform antimicrobic susceptibility testing of all organisms recovered from the endometrial samples in order to assess current antibiotic treatments for women with acute PID are appropriate, 4) assess the presence of novel endometrial pathogens in the lower reproductive tract using vaginal samples obtained from women at enrollment through specific nucleic acid probes developed from nucleic acid of unique organisms recovered from the endometrial samples and 5) perform full genomic sequencing of some of the novel bacteria recovered from women with acute PID and/or histologic evidence of acute endometritis in order to establish the identity and correct taxonomic placement of these organisms. At the conclusion of the proposed studies, the role and identity of novel organisms associated with PID will be identified and may form the basis for improved treatment strategies. This project will be supported by Core B, Project 1 and Project 4.